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