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