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