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