I experimented with the colors of Parthia in my last campaing with them. The huge purple mass didn't fit me :)... I will give you the color code when i come home on my comp.
Just a word of advice. Careful when you hit the marians. I wasn't. The units are awesome, and i started training them like crazy, upgrading goverments, barracks... I had almost half a million mnai, and a few years later i was in the red!!! Didn't know what happened! I forgot that the legionaires were more expensive then the Polybian legions, didn't even look for the cost of the Antisegnani etc.

I had to take an hour to stabilize my economy. Disbanded many armies, fleets. It almost costed me a few settlemets, since i could recruit new legions. Lol... At least i'm back to 200k now :D