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