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