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