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