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