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