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