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