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