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