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