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