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