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