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