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