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