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