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