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