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