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