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