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