It can be made 2 ways. The first is by adding it to the mix. Which
is the easiest and best way to color it in my opinion.
Some of the reasons are that the color will be mixed in well and
the concrete will be the same color throughout the whole slab. So
if your slab chips, it will be the same color.
The second way of coloring is to apply a pigment to the top of
the concrete when troweling. This product is called color hardener,
and comes in many different colors. It usually penetrates the concrete
1/16 to 1/8 inch. This method has its disadvantages, some being
it is very dusty and you usually have to go over it twice to darken
up some of the lighter spots( to make it uniform).
Colored concrete can have any type of finish you like. including
broom or troweled finish.