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