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