Hello Victor John,
Our Sitara SDK does not come with X11. X11 has a lot of dependencies, so you might want to try to use OpenEmbedded to generate all the packages you need. We have some training on OpenEmbedded that might be helpful to you: http://processors.wiki.ti.com/index.php/Sitara_Linux_Training:_Getting_Started_with_Openembedded.
Also, have you looked into the community Angstron and Ubuntu distributions for BeagleBone? I'm pretty sure both of those have X11 ready to go, so maybe that would be an easier path for you to take. Keep in mind, though, that none of those community distributions are supported by TI, but rather by the community: http://beagleboard.org/Community/Forums.
Regards,
Josh