Snow White influences?

well, the obvious similarity of the story... an "innocent girl" who "runs afoul" of a sorceress (or coven of witches in Suspiria) who uses dark magic to inflict pain and suffering on the protagonist. In that way it's similar...
and maybe because Jessica Harper kinda looks like Snow White (pearly white skin, pretty, dark hair, naïve, and a certain "tenderness" about her).

But that's all I can see as similarities.

I can see how the "Technicolor vibrancy" would be an influence on Dario Argento, he has enormous visual flair in his films.... but most of the visual flair of Dario Argento was primarily influenced by Mario Bava.

I think the Snow White influences were primarily visual and imaginative: The idea of a virginal maiden in danger from a malevolent witch, though it varies significantly from the narrative of Snow White (no dwarfs, no stepmother, etc.), was clearly an imaginative touchstone for Argento. Jessica Harper just LOOKS so much like Snow White! And I think tonally, Argento was trying to recapture the sense of menace evoked by classic European fairy tales. Apparently, Argento had originally conceived the film as consisting of young children facing brutal supernatural forces, but his financiers understandably resisted that idea! In any case, that anecdote illustrates what he had in mind, and in a way, I wish his vision had been realized in that respect. He wanted an archetypal confrontation between the purity and innocence of childhood against the corrupting influence of evil. In a peculiar way, Suspiria still defiantly aims in that direction despite the imposed constraints on Argento's full sinister vision. The characters still ACT like children in a dreamy and surreal manner that contributes to the eerie quality of the film, so it's clear that the script was hardly modified at all to accommodate older characters....

But the visual style is clearly indebted to the Expressionistic technicolor dreamscape of Disney's Snow White. This influence is most obvious when Suzy Bannion is running through the school as it collapses around her. Visually, this resembles Snow White's frightened trek through the forest: the visual parallels are remarkable! Note Suzy's straining to escape in cumbersome high heels that subliminally increases the audience's sense of her vulnerability as she throws her arms around her face. This is Snow White's characteristic pose during her intense Odyssey through the woods...


And you will know my name is The Lord when I lay my vengeance upon thee!

I think it's more about the visuals and the atmosphere, rather than general story influences. Inferno and Mother of Tears also have some fairy tale influences but if I told you which you'd have a hard time finding similarities.