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