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)(15,22)(16,27)(17,20)(18,24)(19,23)(21,25)(26,28) involution — undirected(1,2)(3,4)(5,7,8,12)(6,9,10,11)(14,20)(15,25)(16,26)(18,19)(21,28)(22,27)(13,15,17,26)(14,21,20,27)(16,19,25,18)(22,23,28,24)(2,4)(13,16,17,25)(14,22,20,28)(15,18,26,19)(21,24,27,23)(6,10)(9,11)(14,20)(21,27)(22,28)(23,24) 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.