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