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