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