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