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