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