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