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