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