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