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