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