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