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