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