When I first made this compound using Stella 4d (available here), these are the colors the software automatically selected.

I wanted to find a better coloring-scheme, so I told Stella to color the model as a compound. Here’s what I got.

Next, I tried “color by face type.” This yields four colors, instead of just two.

I then tried “rainbow color mode,” with this result.

One more try (color by face, unless the faces are parallel) gave me my favorite color scheme for this compound.

Which one do you like best?