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