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