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