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