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