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