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)(11,14)(12,16)(13,21)(15,17)(18,22)(19,24)(20,23)(1,2)(3,6)(4,7)(5,8)(9,11,15,12)(10,16,17,14)(13,19,22,20)(18,24,21,23)(25,26)(27,32)(28,33)(29,37)(30,31)(34,38)(35,36)(39,40)(1,3,5,4)(2,6,8,7)(10,17)(11,12)(13,22)(23,24)(26,31)(28,32)(34,37)(36,39)(9,12,15,11)(10,16,17,14)(13,20,22,19)(18,24,21,23)(25,27,30,33)(26,32,31,28)(29,35,38,40)(34,39,37,36)(9,13,15,22)(10,18,17,21)(11,19,12,20)(14,23,16,24)(25,28,30,32)(26,33,31,27)(29,36,38,39)(34,40,37,35)(1,4,5,3)(2,7,8,6)(9,14,15,16)(10,11,17,12)(13,23,22,24)(18,19,21,20)(25,29)(26,34)(27,35)(28,36)(30,38)(31,37)(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.