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