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