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