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