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