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)(11,18)(12,20)(13,15)(14,16)(17,22)(19,23)(21,24)(25,26,31,30)(27,32,34,29)(28,33,37,38)(35,39,40,36)(3,7)(5,8)(9,11,15,14)(10,16,13,18)(12,21,22,19)(17,24,20,23)(25,27)(26,32)(28,35)(29,30)(31,34)(33,39)(36,38)(37,40)(1,2)(3,5)(4,6)(7,8)(10,13)(16,18)(17,20)(23,24)(27,34)(29,32)(35,40)(36,39) involution — undirected(1,3)(2,5)(4,7)(6,8)(9,12,15,22)(10,17,13,20)(11,19,14,21)(16,23,18,24)(25,28)(26,33)(27,35)(29,36)(30,38)(31,37)(32,39)(34,40)(1,2)(3,5)(4,6)(7,8)(9,13,15,10)(11,16,14,18)(12,20,22,17)(19,23,21,24)(25,29)(26,27)(28,36)(30,34)(31,32)(33,35)(37,39)(38,40)(9,14,15,11)(10,16,13,18)(12,19,22,21)(17,24,20,23)(25,30,31,26)(27,29,34,32)(28,33,37,38)(35,39,40,36)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.