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