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