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