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