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