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