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