There is an underlying layer of white reflecting cells known as leucophores.
Color comes from organs full of pigment cells known as chromatophores .
Chromatophores contain different types of pigments that result in different colors. Reds, yellows, brown and black are represented by the chromatophores. Other colors such as green and blue seem to be produced by a different group of reflecting cells call iridiphores. Click on the image at left to zoom even closer for a look at the chromatophores.