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