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