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