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(5,7,8,12)(6,9,10,11)(14,18)(15,21)(16,23)(20,24)(22,25)(26,28)(2,4)(13,14,17,20)(15,19,22,27)(16,24,23,18)(21,26,25,28)(6,10)(9,11)(15,22)(19,27)(21,25)(26,28) involution — undirected(7,12)(9,11)(13,15)(14,19)(16,25)(17,22)(18,26)(20,27)(21,23)(24,28) involution — undirectedA 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.