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