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