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