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