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