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