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