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