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