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