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