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