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