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