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