I assume you are talking about Neogonodactylus wennerae from the Tampa area. This species reaches a maximum size of around 7 cm. Colors depend on habitat and depth from which the individual was collected. Most are brown, orangish, or green. In a lighted aquarium, they will often change color after a few months to green, but it requires a molt to do this.
I'm not sure what you mean by a "colorful" animal. The quick answer is that N. wennerae is as colorful as any species I know from the Gulf of Mexico. N. curacaoensis does get into the Keys and has spectacular colors, but you don't find it in live rock shipments from Tampa.
If you mean Odontodactylus scyllarus, the "clown", "painted", or 'Harlequin" mantis, it is from the Indo-Pacific.
Gonodactylus