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