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)(13,14,18,22)(15,23,25,20)(16,17,21,19)(24,27,28,26)(6,9)(10,12)(13,15)(14,20)(16,24)(17,26)(18,25)(19,27)(21,28)(22,23) involution — undirected(13,16,19,14,18,21,17,22)(15,24,27,20,25,28,26,23)(2,4)(15,25)(20,23)(24,28)(26,27) involution — undirected(5,7,8,11)(6,10,9,12)(13,17,18,19)(14,21,22,16)(15,26,25,27)(20,28,23,24)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.