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