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