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