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