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