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