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