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