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