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