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