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