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