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