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