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