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