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