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