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