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