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