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