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