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