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