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