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