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