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