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