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