The technology employs a contrasting color scheme on different surfaces for sensor housing assemblies mounted on exterior parts of a vehicle that is configured to operate in an autonomous driving mode. Lighter and darker colors may be chosen on different surfaces according to a thermal budget for a given sensor housing assembly, due to the different types of sensors arranged along particular surfaces, or to provide color contrast for different regions of the assembly. For instance, differing colors such as black/white or blue/white, and different finishes such as matte or glossy, may be selected to enhance certain attributes or to minimize issues associated with a sensor housing assembly.