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