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