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