I'm not qualified as an expert, but I like to think I know a lot about this topic. Bulk and strength often have very little correlation. Of course, there is a baseline you have to think about - someone who lifts crazy weights isnt going to look like someone who never lifted before in their lives. However, once you get to peak athleticism, it all depends on how you train.
Bodybuilders train for hypertrophy. Their workout regimen (and diets and drugs) are tailored for one thing - to get big. They arent the fastest nor are they the strongest. They just train for size and aesthetics. Its actually difficult to find bodybuilders, or bodybuilder-esque physiques that are actually "athletic".
Boxers, on the other hand, train for strength, speed, and accuracy. Depending on your weight class, there is a different method of training - lightweights tend to go for speed and swift strikes, heavyweights tend to go for overall amount of force. Heavyweights tend to be bulky because of who and how they need to fight. They dont mind having a bit more mass, since mass helps insulate your frame from punches and/or provides more leverage behind a punch. If youre bulky and fast, youre basically a once-in-a-lifetime heavyweight fighter (think Mike Tyson).
Tone is less about muscle and more about bodyfat percentage. Again, there is a baseline here - you need some muscle to look toned, or else youre just going to look skinny and scrawny. However, whether youre 6 ft 200 or 6ft 250, getting down to 5% bodyfat will make both people toned. Muscle mass actually looks very similar, whether its oriented for strength, speed, or size.
This is a picture of Long Qingquan, who destroyed World Records in the Clean and Snatch at the Olympics in Rio:
https://metrouk2.files.wordpress.com/2016/08/587142848.jpg?w=620&h=413&crop=1
Would you expect him, a 5'1 inch, 120 pound male to be able to pick up 375 pounds and lift it above his head? He looks like he works out, but he doesnt look super muscular or anything. Its because while he is one of the strongest people in the world, his training is tailored for strength and speed. You dont need excessive bulk to lift heavy weights.
To the post topic, Ashe's body is supposed to be nimble. She isnt interested in hypertrophy or gaining muscle mass - she primarily relies on strength and speed. Yes, Ashe has lean muscle, but you shouldnt associate that size with strength or speed.
If you look at some of the top women archers in the world, they arent bulky either. Choi Mi-sun is currently considered the best female archer in the world. She is 5'6, 120 pounds.
http://www.theasian.asia/wp-content/uploads/2015/10/MEX15_B15_7618-L.jpg
She isnt excessively bulky, nor does she need to be.