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