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