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