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