It's believed that the extinct dinosaurs were of a similar color of today's lizards. Of course, depending on the environment, whether it be desert or rain forest, has a huge impact on the color animals then as they do now. Since the earth was very warm and wet at that time, it makes sense to think that they would have been similar in coloring to the lizards living in rain forests such chameleons, for example.

We assume they were brownish and greyish like the lizards we know today, but the fact is that nobody's ever actually seen a triceratops in the flesh.

Sky blue pink with lemon purple spots?

Nobody knows!

No one really knows as their skin did not survive in the same way as their skeletons.

And, in any case, why are you posting this in the Photography section??