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