We have literally done 1000’s of floors like this and they are all at once different and exactly the same.
They are different insomuch as every slab of concrete is uniquely colored. They can be brown or grey or tan or even bluish or greenish. They all look different from room to room. They all get lighter or darker over time. All the pictures on this page were of the same house. The photo with the slider shows how the color changes when the last coat of stain-guard is applied at the final polish.