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