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