On a scale of 0 to 1, high real numbers are red; high imaginary numbers are blue; mixes are somewhere in between.

f[z_] := { RGBColor[ Re @ z, 1 - (Re @ z + Im @ z) / 2, Im @ z ],
     Point @ { Re @ z, Im @ z } }

pts = Table[ f [ (x+I y)^3 ], { x, -1, 1, .05 }, { y, -1, 1, .05 } ];

Graphics[ pts, Background -> Black ]