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