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