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