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