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