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