Don't worry about gear. If your players have a confident plan to attack a god, it almost certainly won't come down to gear that the god has. Instead, figure out the style of his/her gear and go from there. 20th level npc wealth by level in pathfinder is 159kgp. Pulling random links from the internet, we have 11mgp at 35th level. Short version: "anything a god wears will be enchanted to the god's specifications, choose style over substance and remember that most gods have either divine creation abilities or know someone who does."
Do give the god an iconic artefact. The hand of vecna, the wand of orcus, these are campaign-defining artefacts. The most common interaction between the avatar of a friendly god and PCs is an avatar saying: "It's dangerous to go alone, take this!" (maybe after the PCs recover the "this" in question). So, use the god's artefact and the history of the god's artefact to drive narrative interactions with the game. Figure out what rumors or popular knowledge says about the artefact and stop there. Don't stat out things that you don't want your players to kill and/or possess.
More to the point, don't waste effort on setting details that your players won't interact with. There is plenty to prep in a world with limited time that your players can encounter. Designing high level NPCs of whatever stripe is not a useful use of time unless your players have clearly telegraphed the session before that they plan to fight that character. Figure out what narritive support is needed and move on.