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