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