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