< a color randomly and at the same time you seem to be asking about assigning specific colors to types which then does not sound random to me.

look at the previous cube : it has different colors for the edges, and different colors for the faces
so each types has different colors in the same time ;)

In some program no random colors gives for example axes direction : red, green, blue as X,Y, Z
so you can easily see if your volumes is // to the axes :)

here it's just for artistic purpose like a Mondrian over steroïded :)

PS Thx for the remember color post :)