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