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