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