It is changes in vote share, not margin... you can find those maps elsewhere.
Anyway, I made a series of these (because bored at work), first of all:
Trump vs McCain
Blue wins this map, and the problems we had with Utah continue and now will start to apply to West Virginia. D/R 90%> is anything above 12 percentage points ftr. Of interest, here: Indiana and Alaska, which show the greatest GOP drop in this period outside of Utah mainly down to Palin no longer being on the ballot I would suppose.
Trump v Bush 2004 (i.e. The Last GOP victory)
One thing to note about these four elections: Oklahoma has been ridiculously stable in its GOP vote share. But not even in the Rust Belt did Trump really improve upon W, only in Appalachia did he make big gains. We must not forget that West Virginia is an anomaly.
Trump v Bush 2000
Now this is more interesting, as Bush lost the popular vote too we can get a better picture which isn't so distorted by the national result. A few things: lol Florida, note the DC Metro area, and Vermont really is unusual in New England.
Now, let's get strange...
Trump vs Ford 76
Here there are quite a few states - in the West, in the South and New England where the change is more than 12 points and many more where it is above 10. This looks much more like a modern election map (unsurprisingly) although there are some strange ones, like Nebraska. Also clear that at this point Florida, Texas, and North Carolina were not like the rest of the South. And Virginia too, obviously. Also is Pennsylvania really unambiguously part of the North East? Trump did worse in Wisconsin than Bush either time or Gerald Ford, but unlike them all, he won the state.
And Finally, Nixon 1960
Florida, North Carolina, and Virginia again. Rhode Island also stands out, and Wyoming. All three West Coast states are 12%+ changes against the GOP, as is Maine and Vermont (RIP Alf Landon). DC couldn't vote in 1960, but I'm pretty sure that Nixon would have done better than Trump's 4% - Nixon in 1968 got 18% after all.