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