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