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