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