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