There are a few ways to discuss the style of this novel. To speak generally, this novel employs modernist methods of story-telling (and explores modernist themes). Characteristics of the novel that qualify as modernist include the fluid sentences that are often used impressionistically.
The passages that can be thus described are often examples of stream-of-consciousness narration, which is often associated with modernist literature.
Instead of telling the story in a straight-forward manner, Faulkner often chooses to use details and implication and even after-effects to indirectly draw the action of the novel. When Granny is killed, the narrative does not directly state that she is dead but rather describes her from Bayard's point of view, depicting her as still and small and old but never clearly stating that she has died. The next scene in the novel is Granny's funeral. In this way, details and after-effects have been used to indirectly communicate the novel's action.
Discussing the style of the narrative, we would also want to discuss the fact that the book was written and published as a series of linked short stories and it is written from a first person perspective.
Bayard's reflective narration, where sometimes he is looking back at events from the perspective of maturity while at other times he is a character enmeshed in the action, is a key to the manipulation of the tone of the scenes. (eNotes)
The limitations of perspective inherent in a first person narrative voice is reflected in a quote from Bayard's narration of the story.
“There is a limit to what a child can accept, assimilate; not to what it can believe because a child can believe anything, given time, but to what it can accept, a limit in time, in the very time which nourishes the believing of the incredible.”