\documentclass[letterpaper]{article}
\usepackage{amsmath,unicode-math,geometry}
\setmainfont{Latin Modern Roman}
\setmathfont{Asana Math}
\usepackage{xcolor}
\usepackage{graphicx}

\begin{document}

Let's try some color...

Now how about some \textcolor{red}{Red}

Here's blue... \textcolor{blue}{Blue}

And green... \textcolor{green}{Green}

Now cyan... \textcolor{cyan}{Cyan}

Now magenta... \textcolor{magenta}{Magenta}

Now yellow... \textcolor{yellow}{Yellow}

And gray... \textcolor{gray}{Gray}

And done.

\end{document}

