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