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