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