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