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