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