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