One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,9)(8,10)(11,12)(13,14,20,27,19,23,18,22)(15,24,25,17,16,21,26,28)(5,6)(7,11)(8,10)(9,12)(13,15,19,16)(14,17,23,28)(18,25,20,26)(21,27,24,22)(2,4)(5,7,8,12)(6,9,10,11)(13,16,19,15)(14,21,23,24)(17,27,28,22)(18,25,20,26)(7,12)(9,11)(13,17,20,21,19,28,18,24)(14,16,27,26,23,15,22,25)(6,10)(9,11)(13,18,19,20)(14,22,23,27)(15,25,16,26)(17,21,28,24)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.