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