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