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