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