Sepia apama skin posesses a dense layer of pigmented chromatophore organs of 3 color classes: yellow, red, and black/brown, as well as underlying structural reflectors of 2 types: iridophores (creating iridescence in the skin ) and leucophores, which produce whiteness in their body patterns. They also have controllable skin papillae that can dramatically alter their appearance. The overall appearance of the animal - termed the body pattern - can change in less than a second due to direct neural control of the skin patterns. This is unique among all animals but is characteristic of cephalopods.

Reference

Oceanworld Cuttlefish Fact Files