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