A fundamental question in the study of consciousness is "To what extent are sensory experiences equivalent between individuals?'' One promising approach is to intersubjectively compare the similarity relationships of sensory experiences, named "qualia structures''. An issue with existing methods is the assumption that sensory experiences evoked by the same stimuli must be matched across participants, precluding the possibility that "my red'' might be "your blue''. To address this limitation, we present a novel method for assessing the degree of similarity between qualia structures without assuming any correspondence between experiences across individuals. Our approach, based on Gromov-Wasserstein optimal transport, aligns subjective experiences in a purely unsupervised manner, using only their subjective relationships. As a proof of concept, we applied our method to a large-scale dataset of color dissimilarity judgments and found that qualia structures can be aligned solely based on the subjective relationships between experiences. This method offers a new means of quantitatively investigating the structural properties of subjective experiences.