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