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