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