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)(13,14,16,19)(15,21,24,18)(17,20,23,26)(22,27,28,25)(5,7,8,12)(6,9,10,11)(15,22)(17,23)(18,25)(20,26)(21,27)(24,28)(1,2,3,4)(6,10)(7,12)(13,15,23,28,16,24,17,22)(14,18,26,27,19,21,20,25)(6,10)(9,11)(15,24)(18,21)(22,28)(25,27) involution — undirected(13,15,17,22,16,24,23,28)(14,18,20,25,19,21,26,27)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.