You can color the snub cube with three colors as follows: Divide both sets of modules into three equal number of colors. With the tr--sq modules, make six squares, two of each color. Take the square of color 1. You'll note from the picture that each vertex of the square has three tr--tr modules incident to it. On one vertex, make these of color 2-1-2. On the next, make them 3-1-3. On the next, make them 2-1-2 again, and on the final vertex, make them 3-1-3 again. This is how it will work with all squares -- if a square is of color y, then one pair of opposite vertices will have modules ordered x-y-x, and the other pair will have modules ordered z-y-z. It works out so that each pair of squares is on opposite faces, and the pattern is pleasing. To get a snub cube from four colors, simply do the same as above, only make all the tr--sq modules out of color 4. The ordering of the tr--tr modules should be the same.