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