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