It would be both colour (bright and/ or "Southwest") and the actual pattern. Search under "Aztec" quilt patterns. Here is an example to get you going:
http://www.quilterscache.com/A/AztecLogsBlock.html
You also might want to look at "Eye of God" -- ojo de Dios -- examples. I think there is on of the Quilterscache site as well.
And, not a quilt, but here is a pic of traditional Mexican blanket designs that could easily be translated into a quilt pattern:
http://www.bing.com/images/search?q=...electedIndex=0