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