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