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