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