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