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