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