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