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