Diatomaceous earth will not help. That is meant for ground-dwelling pests. Soap spray is highly effective. I mix 1 tblspn Dr. Bronners Peppermint Soap with about a liter of water in a spray bottle and it is my go-to aphid killer. They'll die back within a day or two after being coated with it. You have to make sure to spray it on the underside of the leaves though, the ones are the tops of the leaves are just the tip of the iceberg. Also, don't spray it during the day when the sun in shining, it can burn the leaves.
And you can buy lady bugs, lacewings, etc to establish a predator population. I have aphids on all 3 of my hop plants. All three have a nice, large, stable population of lady bugs and their larva. For two of the plants, that's enough, the lady bugs eat about 60 aphids a day. The Zeus, however, was getting overwhelmed, and the lady bugs weren't enough, so I hit the aphis with soap spray and knocked the population down low enough that they're not harming the plant, but there's still food for the lady bugs.
I can look underneath the leaves of any of the 3 plants and find adult lady bugs, a cluster of lady bug eggs, and lady bug larva (which also eat aphids by the dozen). They establish populations like this near good food sources, so on some level, it's good to have some aphids as they will attract predators and give them something to eat so they can reproduce. I only get worried if a plant starts to get enough aphids to curl the leaves, or the aphids are clearly reproducing faster than the predators can eat them and start to take over.