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