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