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