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