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