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