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