One vertex per element, one color per generator, with an edge from x to x·s.
(9,10,13,16)(11,17,18,14)(12,20,21,15)(19,22,24,23)(25,26,29,28)(27,33,36,40)(30,38,34,32)(31,39,35,37)(1,2)(3,7)(4,6)(5,8)(9,11)(10,14)(12,19)(13,18)(15,22)(16,17)(20,23)(21,24)(25,26)(27,31)(28,29)(30,32)(33,37)(34,38)(35,36)(39,40) involution — undirected(1,3)(2,5)(4,8)(6,7)(25,27,34,39,29,36,30,37)(26,31,38,40,28,35,32,33)(2,6)(3,8)(11,18)(14,17)(19,24)(22,23)(25,28,29,26)(27,35,36,31)(30,38,34,32)(33,37,40,39)(2,6)(5,7)(9,12,13,21)(10,15,16,20)(11,19,18,24)(14,22,17,23)(26,28)(31,35)(32,38)(33,40)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.