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