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