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