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