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