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