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