We demonstrate the possibility to produce a blazed grating for electron waves using Kapitza-Dirac diffraction on a standing wave created by several harmonics of a fundamental wavelength. We show that an optimized multicolor standing wave can lead to strongly asymmetric diffraction patterns. Using a bichromatic standing wave, we predict a diffraction probability larger than 50% in a specific order. This order can be chosen with the spatial relative phase between the fundamental and second harmonic. Since the Kapitza-Dirac diffraction grating is experimentally more feasible than Bragg diffraction, this could be an interesting alternative to be used in electron interferometry.