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)(15,26,18,28)(16,27,21,22)(17,24,19,23)(1,2)(3,4)(5,6)(7,10)(8,9)(11,12)(13,15,19,27,20,18,17,22)(14,21,24,26,25,16,23,28)(6,9)(10,11)(13,16)(14,22)(15,24)(17,26)(18,23)(19,28)(20,21)(25,27) involution — undirected(2,4)(5,7,8,12)(6,10,9,11)(13,17,20,19)(14,23,25,24)(15,27,18,22)(16,28,21,26)(13,18,19,22,20,15,17,27)(14,16,24,28,25,21,23,26)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.