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