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