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