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)(11,14)(12,15)(13,16)(17,18)(19,24)(20,23)(21,22)(25,26,31,28)(27,34,33,30)(29,32,38,36)(35,40,39,37)(1,2)(3,5)(4,7)(6,8)(9,11)(10,14)(12,18)(13,21)(15,17)(16,22)(19,23)(20,24)(25,26,31,28)(27,30,33,34)(29,36,38,32)(35,40,39,37)(1,3)(2,5)(4,8)(6,7)(10,12)(11,17)(16,20)(19,21)(25,27)(26,30)(28,34)(29,35)(31,33)(32,37)(36,40)(38,39) involution — undirected(3,8)(5,6)(9,12,15,10)(11,18,17,14)(13,16,23,20)(19,24,21,22)(25,28,31,26)(27,34,33,30)(29,36,38,32)(35,40,39,37)(1,3)(2,6)(4,8)(5,7)(9,13)(10,16)(11,19)(12,20)(14,24)(15,23)(17,21)(18,22)(25,29,31,38)(26,32,28,36)(27,35,33,39)(30,37,34,40)(1,2)(3,5)(4,7)(6,8)(9,14,15,18)(10,17,12,11)(13,22,23,24)(16,19,20,21)(25,30,31,34)(26,33,28,27)(29,37,38,40)(32,39,36,35)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.