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