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