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)(11,12)(13,15)(14,16)(17,18)(19,23)(20,24)(21,22)(25,26,30,31)(27,32,34,28)(29,33,38,39)(35,40,37,36)(1,2,4,6)(3,5,8,7)(9,11)(10,14)(12,15)(13,16)(17,19,21,24)(18,20,22,23)(26,31)(27,34)(33,39)(35,37)(1,3,4,8)(2,5,6,7)(9,11,13,16)(10,14,15,12)(17,18,21,22)(19,23,24,20)(25,27)(26,32)(28,31)(29,37)(30,34)(33,36)(35,38)(39,40)(1,2)(3,5)(4,6)(7,8)(9,12)(10,11)(13,14)(15,16)(17,20)(18,19)(21,23)(22,24)(25,28,30,32)(26,27,31,34)(29,36,38,40)(33,35,39,37)(1,3)(2,5)(4,8)(6,7)(9,11)(10,12)(13,16)(14,15)(17,18)(19,20)(21,22)(23,24)(25,29,30,38)(26,33,31,39)(27,35,34,37)(28,36,32,40)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.