There is no prescibed syllabus or preparation books for the same so you are advised to go through the syllabus which you have studied in your graduation and apart from that, you can download the previous year question papers as these will show the actual paper pattern, important questions and difficulty level of paper.

You can download the papers from below as well -

Http://bhuonline.in/old-qus-paper-entr.html

Good Luck!!!