This is actually a super interesting idea @morkof. I guess the first question is what colors, and do we rely on color alone to indicate the emotion? Red = angry seems clear enough, but beyond that, are other colors clear?
And how we we present the color to emotion palette for people? Correlate colors to emojis? The other option is to leave it totally open and give folks a color palette without dictating the emotional meaning of colors, or without indicating that colors are supposed to correlate with emotions. But this feels like a missed opportunity to speak a language to each other with the colors.
I like making this explicit, but would like to see the idea developed more.