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