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