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