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