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