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