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