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