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