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