One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(6,9)(10,12)(13,14,19,20)(15,17,18,16)(23,24)(27,28)(13,15,19,18)(14,16,20,17)(22,26)(27,28)(1,2)(3,4)(13,16,19,17)(14,15,20,18)(21,22,25,26)(23,27,24,28)(1,2)(3,4)(5,6)(7,10)(8,9)(11,12)(13,17,19,16)(14,15,20,18)(21,23,25,24)(22,27,26,28)(5,7,8,11)(6,10,9,12)(13,18,19,15)(14,16,20,17)(21,24,25,23)(22,28,26,27)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.