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