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)(14,18)(15,22)(19,21)(23,28) involution — undirected(6,9)(7,11)(13,14,16,18)(15,20,22,25)(17,19,24,21)(23,26,28,27)(2,4)(14,19)(17,24)(18,21)(20,26)(23,28)(25,27) involution — undirected(6,9)(10,12)(13,15,16,22)(14,20,18,25)(17,23,24,28)(19,26,21,27)(5,7,8,11)(6,10,9,12)(14,21)(17,24)(18,19)(20,27)(23,28)(25,26)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.