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