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