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