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