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