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