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