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