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