The skin of the colossal squid is considerably thicker than that of the giant squid. As shown in the photo the colossal squid skin has at least two layers, the outer one of which quite resembles that of Architeuthis (giant squid).
The inner skin covering the muscles is gelatinous in nature and contains somewhat larger chromatophores. The latter are the little red dots that you can see on the photo. They are pigments containing cells that can contract or expand, determining the colour of the animal.
The outer skin contains many more smaller chromatophores but is only paper thin when compared to the inner skin, which is at least 2 cm thick in places.
The skin of the giant squid appears to have only one layer, resembling the outer skin of the colossal squid.