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