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