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