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