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