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