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