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