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