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