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