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