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