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