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