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