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