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