Question

why does the color intensity of some organisms appear different from others

Answer 1

Certain animals possess the feature called bioluminescence. They look iridiscent while others don't. This is mostly seen in the marine wildlife.

The pigments the animals possess, their genetic makeup(for synthesizing the pigments, their receptors, their placement) and this is largely reflective of what the animal looks like. Any variation in these factors brings about different intensities in animals.