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