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