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