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