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