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