I was wondering if you can have more than one god card in your deck. Can I? Can they be different colors?
"God" is a creature type just like any other, e.g. "Elf". No rule limits the amount of creatures of the same type you can have in your deck, and no rule limits you to only one color god.
The only limit regarding "N cards of a certain quality" care about the card name, where most formats limit you to 4 cards of the same name, unless they're restricted/banned. None of the cards with the creature type "God" are, though.
All Gods are also (currently, not generally) legendary creatures, which means you may only control one god of each name on the battlefield at the same time (e.g. you can control an Erebos and a Nylea, but not two Ereboses). That's because of the legendary rule, which means if you ever control two Legendary cards with the same name at the same time, you have to put all but one of them into your graveyard. This is what I suppose makes you ask this question.