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)(11,17)(12,22)(13,18)(14,19)(15,16)(20,21)(23,24)(25,26,32,36)(27,37,39,33)(28,30,29,34)(31,35,38,40)(1,2,4,6)(3,5,8,7)(10,16)(13,19)(17,22)(20,23)(25,27)(26,33)(28,35)(29,40)(30,31)(32,39)(34,38)(36,37)(1,2)(3,5)(4,6)(7,8)(9,11,15,12)(10,17,16,22)(13,20,19,23)(14,24,18,21)(25,28,32,29)(26,34,36,30)(27,35,39,40)(31,33,38,37)(1,3)(2,5)(4,8)(6,7)(9,12,15,11)(10,17,16,22)(13,23,19,20)(14,24,18,21)(25,29,32,28)(26,30,36,34)(27,35,39,40)(31,33,38,37)(9,13,15,19)(10,18,16,14)(11,20,12,23)(17,21,22,24)(25,30)(26,28)(27,38)(29,36)(31,39)(32,34)(33,40)(35,37)(9,14,15,18)(10,19,16,13)(11,21,12,24)(17,20,22,23)(25,31,32,38)(26,35,36,40)(27,30,39,34)(28,37,29,33)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.