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