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