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