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