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