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