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