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)(27,33)(28,35)(38,40)(1,2)(3,5)(4,6)(7,8)(9,11,16,23)(10,17,20,24)(12,21,13,19)(14,15,18,22)(25,26,30,31)(27,29,33,39)(28,36,35,32)(34,40,37,38)(2,3)(6,7)(9,12,16,13)(10,18,20,14)(11,19,23,21)(15,24,22,17)(25,27,30,33)(26,29,31,39)(28,37,35,34)(32,40,36,38)(4,8)(6,7)(9,13,16,12)(10,18,20,14)(11,21,23,19)(15,24,22,17)(25,26)(27,29)(28,32)(30,31)(33,39)(34,38)(35,36)(37,40)(1,3,5,2)(4,7,8,6)(9,14,16,18)(10,12,20,13)(11,22,23,15)(17,19,24,21)(25,28,30,35)(26,32,31,36)(27,34,33,37)(29,38,39,40)(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)(26,33)(27,31)(28,38)(30,39)(32,37)(34,36)(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.