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