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