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