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