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