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)(11,15,19,22)(12,20,21,17)(13,18,23,24)(25,26,30,29)(27,31,36,34)(28,32,38,37)(33,39,35,40)(1,3,5,8)(2,6,4,7)(9,11)(10,15)(12,18)(13,17)(14,19)(16,22)(20,23)(21,24)(25,27)(26,31)(28,35)(29,34)(30,36)(32,40)(33,38)(37,39)(1,2,5,4)(3,6,8,7)(10,16)(11,19)(17,20)(18,24)(25,28)(26,32)(27,33)(29,37)(30,38)(31,39)(34,40)(35,36)(9,11)(10,15)(12,18)(13,17)(14,19)(16,22)(20,23)(21,24)(25,29,30,26)(27,34,36,31)(28,37,38,32)(33,40,35,39)(1,2,5,4)(3,6,8,7)(9,12,14,21)(10,17,16,20)(11,18,19,24)(13,22,23,15)(25,28)(26,32)(27,35)(29,37)(30,38)(31,40)(33,36)(34,39)(1,4,5,2)(3,7,8,6)(9,13)(10,18)(11,17)(12,15)(14,23)(16,24)(19,20)(21,22)(25,27)(26,31)(28,33)(29,34)(30,36)(32,39)(35,38)(37,40)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.