Define plain colors linked with category in Geo Chart

[ZioTonio]

Hello,

I'm wondering how to do a very simple data representation with looker. I want to draw a map displaying regions and colors linked with category (2 categories = 2 different colors, 3 categories = 3 different colors, etc...). Each region is linked with a category and is colored with the associated color.

It seems very simple on the paper. Take a look at the picture below for a use case (US electoral map).

Do you know if it's possible to do it with looker?

I can draw a geochart and linked region with a metric (it will color the map with gradian) but in my situation it's not appropriate. I want a plain color for each different category...