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