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