The color is there but you use a processing program - not SGP - to bring it out. You can stack the images in a free program like Deep Sky Stacker and then process that image in a processing program like Photoshop, StarTools, Gimp, Pixinsight etc. Its in these programs that you deal with color.
If you are new with this, I would recommend you go to more general discussion group on imaging. The forums on Cloudy Nights - especially the Beginning and Intermediate Imaging Forum - ia an excellent place to get more information on overall processing images.