Unfortunately, there are no clear rules about entirely disguising drones, vehicles, or anything else of that nature. Thus, I cannot give you a strict Rules as Written answer. However, I can give you one option for hiding weapons, and then a logical one rooted in the actual rules, and rooted in my own experience for disguising an entire drone.
So, to start, you have two options here. The first is a simple RAW answer:
Concealed weapon mounts are detailed in Rigger5. If you're using the Drone customization optional rules, 'Pop-out mounts' are detailed on page 124. If you're using normal vehicle modification rules, concealed weapon mounts are detailed on page 163. These are mounts that are hidden inside of the body of the Drone (or at least covered by plating of some sort), and are thus concealed that way. So, you could install concealed weapon mounts on your Drone, and also install, say, a Camera. Or you arm a utility drone like the EVO Proletarian with concealed mounts.
If you pair your armaments with leaving these drones equipped with normal gear, then this should work out just fine. For your 'Camera Drone' example, here is what you could do:
You get yourself a Horizon CU3 camera drone and install either a Mini-mount with blow-away panels (single-use disguise), or a Micro-mount that is retractable.
The Custom Option
While running a prior SR5 game, I had a runner team ask to do something similar. They were trying to disguise their weapons as something mundane that would pass a cursory inspection
The way I handled this was with a complex test that used the Disguise skill to invent good designs for the disguises, then I had them use the Armorer skill or Artisan skill to fabricate their disguises...depending on the idea they had for how to hide their weapon.
One example of this was a player who modified a guitar to act as a sheathe for his sword. The blade went in the neck, and the hilt was in the bowl...he'd have to break the guitar to get the sword out, but that was fine with him. It actually ended up working out great...because he put the guitar in a case. So when security opened the case (everyone has heard of the 'hide a gun in the guitar case' trick), they saw a guitar and went 'right, okay then, move along.'
I then used their average result on the Disguise test and Crafting test for how good the disguise would hold up to inspection (A poorly made brilliant design, and a poorly designed but flawlessly crafted design are both still reasonably workable)
This worked out great as they collaborated to get their designs put together and ready to go.
For your particular case, I would recommend modifying what I did above, and using whatever 'Mechanic' skill is used to service and modify that Drone (Aeronautics, Automotive, etc) for the fabrication part. I would also recommend taxing the drone's Modification slots in the same way that Concealed Mounts tax them ('free' for a single-use disguise that is destroyed when you use what it hid...1 mod point for a re-usable disguise).
Really, what this would amount to is taking the 'Pop-out Mount' modification from Rigger5, and using a Disguise check against it to design your modification so that it looks like something else, rather than just being metal plates covering a gun.
The first option is your simple go-to if you want a mundane looking drone to have hidden weapons on-board. The second option is if you want the drone to have exposed weaponry, that you wrapped in something to make it look innocent...such as building a camera-body around the barrel of a gun.