140lbs would be a monster cheetah, a more typical average is 80-120 lbs.
Leopards vary a lot by region (they found all over Africa and Asia). Some places they're only 80-120lbs but in other places they go 150+.
But the biggest difference isn't their size, it's what and how they kill.
Typically, cheetahs kill little fast things that they chase down and trip up with their speed (they will literally trip antelope, which sometimes break their necks in the tumble). The cheetahs can finish them off with their claws/teeth of course, but they're built for speed and that's their main weapon.
Here's a pretty typical cheetah action, with a very average prey size:
Now, leopards will go after small prey too (they love monkeys), but they can kill big things as well. They are sneakier, and they kill with their strong limbs and massive jaws. Then they have incredible strength that allows them to carry that stuff all the way up in trees so they can take their time finishing it. They are built for strength.
Here's a leopard doing something no cheetah could ever dream of:
As far as jaguars go, yeah, they're way bigger and stronger. But they rarely kill humans. In zoos they're pretty timid around people. You'd have more trouble physically defeating a jaguar (impossible) than a leopard (just difficult), but the jaguar probably isn't going to attack you in the first place.
Total body count:
Cheetahs: Almost never kill people, I know of no records of them killing an adult man.
Leopards: Kill hundreds of people every year...in fact, in India some leopards have
singlehandedly killed and eaten hundreds of people over the course of several years.
Jaguar: Very rarely kill people. It happens, but it's always a very surprising event.