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