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