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