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