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