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