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