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)(15,19)(16,20)(17,18)(21,22)(23,26)(24,28)(25,27)(6,10)(7,12)(13,15)(14,16)(17,20)(18,19)(21,23,25,28)(22,26,27,24)(6,10)(8,11)(14,18)(15,20)(21,23)(22,24)(25,28)(26,27) involution — undirected(1,2)(3,4)(5,7,9,12)(6,11,10,8)(13,16,17,19)(14,15,18,20)(21,23)(22,24)(25,28)(26,27)(5,8,9,11)(6,12,10,7)(13,15)(14,19)(16,18)(17,20)(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.