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