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)(11,17)(12,16)(13,14)(15,19)(18,24)(20,22)(21,23)(25,26,31,28)(27,34,33,30)(29,32,37,36)(35,40,39,38)(1,2,5,6)(3,7,8,4)(10,13)(12,20)(15,17)(18,21)(29,37)(32,36)(35,39)(38,40)(1,3)(2,4)(5,8)(6,7)(9,11,14,19)(10,15,13,17)(12,21,20,18)(16,24,22,23)(25,27)(26,30)(28,34)(29,35)(31,33)(32,38)(36,40)(37,39)(1,4)(2,3)(5,7)(6,8)(9,11)(10,15)(12,18)(13,17)(14,19)(16,23)(20,21)(22,24)(25,28,31,26)(27,34,33,30)(29,36,37,32)(35,40,39,38)(1,2)(3,4)(5,6)(7,8)(9,12)(10,16)(11,18)(13,22)(14,20)(15,23)(17,24)(19,21)(25,29,31,37)(26,32,28,36)(27,35,33,39)(30,38,34,40)(1,4)(2,3)(5,7)(6,8)(9,13,14,10)(11,17,19,15)(12,22,20,16)(18,24,21,23)(25,30,31,34)(26,33,28,27)(29,38,37,40)(32,39,36,35)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.