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