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