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