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