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)(13,14,18,21)(15,19,25,28)(16,20,17,22)(23,26,24,27)(1,2)(3,4)(6,9)(10,12)(13,15)(14,19)(16,23)(17,24)(18,25)(20,26)(21,28)(22,27) involution — undirected(2,4)(13,16,18,17)(14,20,21,22)(15,23,25,24)(19,26,28,27)(2,4)(5,7,8,11)(6,10,9,12)(15,24)(16,17)(19,27)(20,22)(23,25)(26,28)(6,9)(10,12)(14,21)(19,28)(20,22)(26,27) involution — undirectedA 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.