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