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