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