In this paper, we study relationships between the normalized characters of symmetric groups and the Boolean cumulants of Young diagrams. Specifically, we show that each normalized character is a polynomial of twisted Boolean cumulants with coefficients being non-negative integers, and conversely that, when we expand a Boolean cumulant in terms of normalized characters, the coefficients are again nonnegative integers. The main tool is Khovanov's Heisenberg category and the recently established connection of its center to the ring of observables on Young diagrams, which enables one to apply graphical manipulations to computation of observables on Young diagrams. Therefore this paper is an attempt to deepen the connection between the asymptotic representation theory and the graphical categorification.