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