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