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