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