"She's got a lot of color" is a phrase horsemen and women use to describe a horse who is what is termed a "color" breed (Appaloosa, Paint, etc.) The amount of color can vary, hence the term.
For example, here's an Appaloosa with little color:
See how his spots are mostly on his rump and maybe one or two on his face and shoulders?
Then compare him to this Appaloosa, which would be described as "loud" as in "loud color."
(He's also called a "leopard Appaloosa" which is a distinct coat pattern within the breed.)
There are even Appaloosas with very few spots, and they have their own descriptive terms, too.
These two are "few spot" Appaloosas.
Still full bred Appaloosas, just without many spots.
And this is a "no spot" Appaloosa. He still has the characteristic mottled skin around his face and is a full bred Appaloosa, but there are no spots on his coat.
Personally, I like mine spotted, or "with lots of color."
Like this girl. My "varnish roan" Abby.
Varnish roans have a base coat of intermingled dark and white hairs, with darker patches on the shoulders, bony points, and other areas. The roaning can change over time and with the season, or it may simply remain stable.
The mare above is an "extreme" varnish roan - lots and lots of white.
So is this filly.
My girl isn't an extreme but she is a varnish. Her color changes, mostly in that the white patches come and go. She's darker in the winter and lighter in the summer when she sheds out.
I think she's perfect.