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