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