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