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