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