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