You may change the colours in the editor. But, there you just see the colours, they aren't given numbers or names.
So, this really is no fun.
In PTW, I often noticed the described effect when having a game with Arabs and Chinese. Becomes even more perfect, if both are neighbours, and you want (or have to) to have war with ONE of them....
Personally, I think Civ originally was designed for small maps with up to 6 different nations, as you can see by a lot of other limitations...