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