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