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