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