Needs["Graphics`ArgColors`"] ;
e = 10;
f = y - e (x^3/3  - x);
g = -x;
Plot3D[{Abs[(f + g I)], ArgColor[f  +  g  I]}, {x, -2.5, 
        2.5}, {y, -12, 12}, ImageSize -> {400, 300}]