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