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