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