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