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